1. Field of the Invention
The innovation described herein was the result of a study of several interrelated problems inherent in the construction of road beds, and other similar leveling tasks which are faced on a daily basis by those who do such work.
More particularly, it has been observed that elevating scrapers, such as a Caterpillar.RTM. 623E, or the John Deere.RTM. 862B, identified by way of example of the type of equipment only, tend to load unevenly. As a consequence, the scraper tends to list to the heavy side, and when it does, the scraper blade will tend to dig in on that side, resulting in an uneven cut. Since the function of the scraper is to provide a level cut, the purpose of using such a piece of equipment is severely compromised.
In yet another circumstance, the elevating scraper may encounter topographical changes along the same path. As a result, the left or right set of wheels may be elevated from time to time, which will, of course, adversely effect the orientation of the blade and the resultant cut which the blade can deliver.
2. Overview of the Prior Art
The problems articulated above, and others of a similar ilk, are not uncommon in the use of elevated scrapers and other off road, heavy construction equipment.
To date, the generally accepted solution has been to alter the attitude of the blade itself by use of mechanical or hydraulic means, or a combination of both, and the familiar motor graders are typical of such devices. See also, Ukai Patent 5,037,160, and Rothi et al. Patent 3,695,713.
It will be appreciated, however, that when the blade is attached to bowls having a capacity in the 10 to 15 yard range, adjustment of the blade in any significant amount is not only inefficient, it is extremely difficult and, where possible, highly complicated. Even in today's multi-million dollar construction projects, the ability to perform in a cost effective manner is extremely important, and without the ability to make necessary adjustments from the cab in such equipment, cost effective performance is simply out of the question.
Verhoff Patent 4,067,395, is of general interest only, in that it relates to land leveling equipment in a broad sense. The Verhoff type system is designed primarily for use, in agricultural settings, wherein large fields are to be leveled and graded to provide for, inter alia, tail water run off, as part of the irrigation scheme.
Machinery such as that disclosed in Verhoff, was in extensive use in the late 70's and employed a "gauge frame" to serve as a reference for the adjustment of the main frame to level out high and low spots in the line of travel.
Verhoff type levels have become more sophisticated and are currently in use with laser devices which focus a laser beam at the sensing system 75 to establish a desired height of the machine and, thus, the level at which the land traversed by the machine will be cut.
Verhoff never intended his device to be adjustable in a direction transverse to the forward movement of the blade, and it is incapable of such adjustment.
Verhoff does use a hydraulic motor, and what appears to be an over center linkage, to simultaneously adjust the height of a pair of supporting wheels for the purpose of establishing the depth of the cut to be taken by the device as it is pulled along by the tractor.
Verhoff does not, and can not, as does Applicant, provide transverse adjustment of the attitude of the machine to compensate for uneven loading, nor does it compensate for uneven terrain transverse to the line of travel.